Agree on the names. Why drag old, tired names and plop them on beautiful, 21st Century Automobiles.Maybe there should be two...
Bentley-level car with competitive/superior horsepower
Veyron-killer? Just for attention... It'd be a really low volume car in the 850k price range like mgescuro suggested. Just to break records and get a name out. Personally I've never heard of a Bugatti until the Veyron. I know it was revived specifically for it, but it's all the same. It's an insane car that garnered a lot of attention. It'd also be good for marketing, beating the Bugatti. It's also appease the Sixteen fanboyz. Use the 1300HP engine you suggested. 2 seater coupe. AWD.
They don't need old nameplates. Seville/Deville are dad cars. My dad's had both. They were great, but I would never want a dad car. My dad's also had S-classes. Those aren't dad cars. Eldorado is a tired nameplate. It wouldn't fly as well as a new one. It's not something that means anything to most young people, and quite frankly the name is too clunky. Ciel is a much more beautiful name. It's a new age for Cadillac. Cadillac is finally taking off, why drag it down with old baggage?